The Dingoo a380 is easily the best of the bunch you mentioned, the Ben nanonote seems cool, but as far as I know, it's out of production, and about impossible to find anyone selling it.
None of the systems you mentioned can emulate PS1 or N64 at any playable speed, so if you need PS1 and N64, then none of those options will do....... right now Android devices such as the JXD and Yinlips handhelds and Xperia play and Archos gamepads are really your only options for that..... The GCW Zero will be able to handle them also, but, you'd have to wait until someone ports over and optimizes a PS1 and N64 emulator for the zero, also who knows when or if the zero is ever going to be mainstream production, a zero would be really hard to get right now, you'd have to get lucky and find a used one.
A hacked PSP is also an excellent emulation device for anything up to PS1, and can be found pretty cheap used on ebay, they can even do a little N64, but most N64 titles will not play at full speed.